4.7 Comparing ionic and covalent compounds Flashcards
Metals and non-metals react to form ….
Ionic compounds
Non-metals react to form ….
Covalent compounds
The covalent compounds exist as ….
Molecules
Particles in an ionic compound
are ions
Particles in a covalent compound
are molecules.
Charge in ionic solids.
In ionic solids, the particles are charged and the forces between them are strong.
Charge in covalent solids.
In molecular covalent solids, the particles are not charged, and the forces between them are very weak.
What does a regular arrangement of particles in a lattice always lead to?
Crystals
Properties of ionic compounds
- Ionic comopounds have high melting and boiling points.
- Ionic compounds are usually soluble in water.
- Ionic compounds conduct electricity, when melted or dissolved in water.
Properties of covalent compounds
- Molecular covalent compounds have low melting and boiling points.
- Covalent compounds tend to be insoluble in water.
- Covalent compounds do not conduct electricity.
Why do ionic compounds have high melting and boiling points?
This is because the ionic bonds are very strong. It takes a lot of heat energy to break up the lattice. So ionic compounds are solids at room temperature.
Why are ionic compounds usually soluble in water?
Ionic compounds are usually soluble in water because the water is able to separate the ions from each other. The ions then move apart, surrounded by water molecules.
Why do ionic compounds conduct electricity, when melted or dissolved in water?
A solid ionic compound will not conduct electricity. But when it melts, or dissolves in water, the ions are free to move. Since they are charged they can then conduct electricity.
Why do molecular covalent compounds have low melting and boiling points?
This is because the attraction between the molecules is low. So it does not take much energy to break up the lattice and separate them from each other. That explains why many molecular compounds are liquids or gases at room temperature and why many of the liquids are volatile.
Volatile
Evaporate easily